Racial and ethnic health disparities among elderly patients with chronic conditions is a major challenge affecting our health care system. Many chronically ill minority elderly lack high quality care, have poor health outcomes, and often use emergency departments (EDs) and/or hospitals for routine primary care services. To prevent the unnecessary use of costly health care services and assure minorities achieve best outcomes, attention should be focused on clinics where these patients receive primary care, while taking into account their individual and community characteristics. Nurse practitioners (NPs) disproportionality deliver primary care to minorities and practice in underserved areas. Yet, to date, limited research has focused on the role of NPs and practices employing NPs in reducing health disparities, and little is known about the characteristics of NP practices where minorities receive care and whether the underlying differences in their organizational and structural attributes are barriers to achieving reductions in health disparities. The overarching aim of this study is to understand ways to reduce racial and ethnic disparities in outcomes of chronically ill elderly patients receiving care from practices employing NPs. Our study will take a comprehensive integrated approach to account for patient, community, practice, and state factors as a system determining disparities. Using multilevel and geographic information system methods, we will achieve three specific aims: Aim 1. Assess the extent to which racial and ethnic disparities in outcomes of chronically ill elderly patients are explained by differences between or within primary care practices employing NPs. Aim 2. Determine the effect of a) NP clinical role, b) care environments, and c) structural capabilities of primary care practices employing NPs on racial and ethnic disparities in chronic condition outcomes for elderly patients. Aim 3. Assess the extent to which patients' community characteristics (i.e., socioeconomic position and primary care availability) are related to racial and ethnic disparities in patient outcomes. We will survey NPs and practice managers in 6 states with variable scope of practice laws governing NPs to collect data about structural and organizational features of practices employing NPs and link these measures to community data on socioeconomic factors and Medicare claims data on hospitalization and ED visits. Our multilevel modeling approach will untangle the interrelated effects of the NP role, care environments, structural capabilities, and community factors on disparities in outcomes of elderly patients to point interventions to eliminate health disparities and identify practices and communities that can most benefit from them. If differences in organizational and structural attributes of NP practices are found to be associated with disparities, interventions could be targeted to practices serving minorities. Thus our findings will inform administrators and policy makers seeking ways to reduce health disparities among the elderly through comparatively low cost organizational interventions. The study aligns well with National Institute on Minority Health and Health Disparities' vision of equal opportunity to live healthy lives for all Americans.